function [bool] = isvertical(W)

% isvertical: Find all vertical component waveforms (boolean output)
%  
%  USAGE: [bool] = isvertical(W)
%  
%  INPUTS: W - waveform object array
%                           
%  OUTPUTS: bool - boolean array (same size as W)

% Author: Dane Ketner, Alaska Volcano Observatory
% $Date$
% $Revision$

if ~isa(W,'waveform')
    error('isvertical: waveform object input required')
end

tmp = get(W,'channel');
if ischar(tmp)
    C{1} = tmp;
elseif iscell(tmp)
    C = tmp;
end

for n = 1:numel(C)
    bool(n) = strcmpi(strtrim(C{n}(3)),'z');
end
bool = reshape(bool,size(W,1),size(W,2));